Method of applying to metal or other surfaces a coating of fusible metal



Patented Jan. 3, 1939 UNITED STATES PATENT OFFICE METHOD OF APPLYING T METAL OR OTHER SURFACES A COATING OF FUSIBLE METAL No Drawing. Application October 12, 1936, Se-

rial No. 105,346. In Great Britain October 24,

1 Claim.

This invention relates to a method of applying to metal or other surfaces a coating of fusible metal. The object of the invention is to provide a method which will effect a more secure and dur- 5 able attachment of the coating metal to the surface to be coated than has hitherto been possible.

An important application of the invention is its use for attaching a lead lining to the inner surfaces of cast iron or other metal containers for corrosive liquids, for example the volumes, towers and tanks used in the manufacture of sulphuric acid. The invention may be used with particular advantage in lining containers (such as the chambers of air displacement pumps) which in use are subjected to frequent alterations of pressure, so that a particularly secure attachment of the lining metal is necessary.

The method in accordance with the invention comprises the steps of applying to the surface to be coated a relatively thin layer of a coating metal. After the surface coating is applied, the further lining of lead or lead alloy isplacedthereon preferably in the form of sheets, and the edges thereof are burned together and to the initial coating layer. In certain cases it may be possible to use only a single sheet of the coating metal, but where the shape or size of the surface to be coated render it desirable, a plurality of sheets may be used, the abutting edges of the sheets being fused together at the same time that the sheets are fused to the first coating.

The first coating may conveniently be applied by spraying. Alternatively, where the surface to be coated is of metal or other material which is,

or has been rendered, electrically conducting, the first coating may be applied by electro-deposition.

Thus in applying the invention to the lining with lead of cast iron containers, the inner surface of the container is first electro-plated with lead, 5 or lead or an alloy of lead is sprayed onto the inner surface, to form a uniform, relatively thin lining firmly secured over its entire surface to the container. It has been proposed to line pipes and other suitably shaped hollow members with lead 10 by tinning or zincing the inner surface of the member, then introducing a lead pipe of a smaller diameter, spinning the pipe rapidly about on its axis, and heating it until the lead liquefies and is in contact with the inner surface of the pipe 15 by centrifugal force; but such methods are unsuited to the production of members of the class mentioned herein to be treated by the present method.

It will readily be appreciated that by this 20 method a strong and durable lining is obtained which is securely attached to the container at a large number of points.

What we claim and desire to secure by Letters Patent is: 25 A method of lining with lead a hollow cast iron body comprising the steps of depositing electrolytically upon the inner surface of the hollow body, a thin, uniform layer of lead, applying to this layer sheets of lead and simultaneously burning 30 the edges of the sheets to the edges of the adjacent sheets and to said layer.

WILLIAM HERBERT EXLEY.

WALTER HADDON. 

